Questions for putting up a tiny house? (Rapid City)

New to the area, I want to buy a tiny house, would be on trailer.
What are the rules and regulations for such a thing? Would prefer somewhere in the country, not at all in Rapid.
Any help, answers would be appreciated.
Looking for some average, do I need a building permit? Septic tank? Etc? I e looked at the government websites and local rules and get the click here.
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with no answers!! Let me know.
Thanks!